Symbol.match

main Documentación oficial Licencia CC-BY-SA-2.5Descargado el 2026-08-02

En esta página

Specifications#
Browser compatibility#
See also#

The Symbol.match static data property represents the well-known symbol Symbol.match. The {{jsxref("String.prototype.match()")}} method looks up this symbol on its first argument for the method used to match an input string against the current object. This symbol is also used to determine if an object should be treated as a regex.

For more information, see RegExp.prototype[Symbol.match]() and {{jsxref("String.prototype.match()")}}.

{{InteractiveExample("JavaScript Demo: Symbol.match", "taller")}}

```js interactive-example const regexp = /foo/; // console.log('/foo/'.startsWith(regexp)); // Expected output (Chrome): Error: First argument to String.prototype.startsWith must not be a regular expression // Expected output (Firefox): Error: Invalid type: first can't be a Regular Expression // Expected output (Safari): Error: Argument to String.prototype.startsWith cannot be a RegExp

regexp[Symbol.match] = false;

console.log("/foo/".startsWith(regexp)); // Expected output: true

console.log("/baz/".endsWith(regexp)); // Expected output: false

## Value

The well-known symbol `Symbol.match`.

{{js_property_attributes(0, 0, 0)}}

## Description

This function is also used to identify [if objects have the behavior of regular expressions](/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp#special_handling_for_regexes). For example, the methods {{jsxref("String.prototype.startsWith()")}}, {{jsxref("String.prototype.endsWith()")}} and {{jsxref("String.prototype.includes()")}}, check if their first argument is a regular expression and will throw a {{jsxref("TypeError")}} if they are. Now, if the `match` symbol is set to `false` (or a [Falsy](/en-US/docs/Glossary/Falsy) value except `undefined`), it indicates that the object is not intended to be used as a regular expression object.

## Examples

### Marking a RegExp as not a regex

The following code will throw a {{jsxref("TypeError")}}:

```js
"/bar/".startsWith(/bar/);

// Throws TypeError, as /bar/ is a regular expression
// and Symbol.match is not modified.

However, if you set Symbol.match to false, the object will be considered as not a regular expression object. The methods startsWith and endsWith won't throw a TypeError as a consequence.

const re = /foo/;
re[Symbol.match] = false;
"/foo/".startsWith(re); // true
"/baz/".endsWith(re); // false

Symbol.match

Specifications#

Browser compatibility#

See also#